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Flight 447 'Black Box' Decoded
fermion writes "An initial report has been released by the BEA concerning the details of the last minutes of Flight 447 en route from Rio de Janeiro to Paris. According the report, the autopilot disengaged and stall warning engaged at 2 hours 10 minutes and 5 seconds into the flight. Less than 2 minutes later the recorded speeds became invalid. At 2 hours 14 minutes and 28 seconds, the recording stopped. The final vertical speed was recorded around 10,912 ft/min."
Um no. The washer will hang in the direction opposing the acceleration you are undergoing. If you are upside down in the plane, diving toward the ground at 2G's, it'll feel like one G toward the floor of the plane (up).
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Airbus is run by software. Boeing by pilots.
This is a delusion. Read up on Turkish Airlines Flight 1951. I mean, they programmed 737 to do what? Trust a single radio altimeter known to fail in the worst possible mode, producing false readings? Actually use these readings to automatically enter the landing flare mode with rather subtle indication to the pilots? Autothrottle reverting pilot's inputs? Sounds like scary automation to me.
The reality is, all modern commercial airliners are run by software. If you want an airliner run by pilots, go to Russia and fly some Tupolevs, there are still quite a few left (ehhehe).
My exception safety is -fno-exceptions.
Assuming the average length of a book in the Library of Congress is 300 pages and it takes 3 minutes to read one page, this decent rate can best be expresses as 725,254,818,816 FootballFields/LibraryOfCongress
I swear to God...I swear to God! That is NOT how you treat your human!
What's most interesting in this case is that the systems warned the pilots of an impending stall, but then once they were in a stall, there was no warning at all, as if they had recovered from the stall. That's really unfortunate.
That's because once the airspeed drops below 60 knots, the input from the angle of attack vane is ignored by the flight computer. The computed angle of attack is how the flight computer determines the airplane is approaching a stall, so without a valid input from the AOA vane, the computer can't sound the stall warning. The AOA vane is just a triangle-shaped piece of metal sticking off the side of the airplane on a little lever, so the airflow naturally positions it, just like a weather vane. As the angle of attack changes, the vane moves, providing an input to the computer. Below about 60 knots, though, there isn't enough airflow to move the AOA vane to a reliable, steady position, so the information is discarded by the computer.
In this case, you're right, it was unfortunate because it provided a confusing result to the crew. They had pulled the airplane's nose up into a stall, and when the airspeed dropped below 60 knots, the stall warning stopped. At one point, the crew did lower the nose of the airplane, which caused an increase of airspeed, which is of course precisely what they needed, but as the airspeed increased beyond 60 knots, the stall warning suddenly started back up. That made them think that what they were doing was making the situation worse, not better, when in fact they were doing the right thing. They pulled the nose back up and then never got it back down until they hit the water. Even when valid, the AOA vane never indicated an angle of attack of less than 35 degrees - generally speaking, almost any general or commercial aviation wing will be well into a stall by about 15 or 16 degrees AOA.
Really? Think about that again, please. The astronauts on board the International Space Station are not accelerating... they're in a continous free fall at a constant speed around the Earth (called orbiting).
Think about that again please. The ISS is in a free fall because it is constantly accelerating.
That's what's called orbiting.
What do you think keeps a spacecraft in orbit and from flying off in a straight line?
Yup, constant acceleration by gravity.
Acceleration in the physical sense doesn't always mean "change of speed".
If the acceleration is always perpendicular to an object's movement, it means
"change of velocity without change of speed", and that's exactly what
happens in a circular orbit. No, velocity and speed aren't the same thing.
It's randomly on a car forum, but its worth a read. Some guys that know what they're talking about talk about what they think happened. They also include pics of various airbus cockpits for reference.
http://www.mye28.com/viewtopic.php?t=64381&postdays=0&postorder=asc&start=25
Here's the basic story, as I understand it:
- the pilots flew into a thunderstorm
- they were 100% blind, relying entirely on the glass-screen instruments
- once all 3 pitots froze, the redundant computers started disagreeing and then finally agreed that things were ugly
the effect in the cockpit is that a serious of cascading failures were unfolding, likely overwhelming the pilots.
additionally, there would be NO functional indicators for alt, speed, horizon, etc. Once the computers have faulted, they no longer share that information.
Also, as the computers degrade authority, in an Airbus the pilots get MORE control of the aircraft. This means that controls move through larger ranges.
As flight control reverts to failsafe mode, the controls in the cockpit do not "auto-zero". And the forcefeedback goes off line.
Effectively, the pilots are 100% blind, and the inputs they make have no feedback whatsoever. They cannot even tell if they have _stopped trying_ to turn.
Imagine being blindfolded. Your job is to put the end of a 4 ft long stick inside of a 1" circular hole in the floor. Except the stick is a peice of yarn.
That's what their instruments and control apparatus were like.
Now imagine that everything is beeping at you and you are in a plane in a thunderstorm, over the ocean, at night, and everything outside is total blackness.
You're fucked. Thoroughly and completely fucked.
My opinions are my own, and do not necessarily represent those of my employer.
No, because in most jets extra thrust will actually push the nose up since the engines are located under the wing. The most recent procedures actually have you reduce thrust to bring the nose down more quickly.
I'm an Airbus pilot, and have flown Airbus airplanes in two different companies. Before the incident, I had never been trained on stalls in alternate law, since this was deemed to be an unlikely scenario. The only stall-related exercise was the "impending stall" under normal law. Under alternate law, only normal flying was trained.